// MIT License

// Copyright (c) 2019 Erin Catto

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#include "settings.h"
#include "test.h"

/// This test shows how to use a motor joint. A motor joint
/// can be used to animate a dynamic body. With finite motor forces
/// the body can be blocked by collision with other bodies.
class MotorJoint : public Test
{
public:
  MotorJoint()
  {
    b2Body* ground = NULL;
    {
      b2BodyDef bd;
      ground = m_world->CreateBody(&bd);

      b2EdgeShape shape;
      shape.SetTwoSided(b2Vec2(-20.0f, 0.0f), b2Vec2(20.0f, 0.0f));

      b2FixtureDef fd;
      fd.shape = &shape;

      ground->CreateFixture(&fd);
    }

    // Define motorized body
    {
      b2BodyDef bd;
      bd.type = b2_dynamicBody;
      bd.position.Set(0.0f, 8.0f);
      b2Body* body = m_world->CreateBody(&bd);

      b2PolygonShape shape;
      shape.SetAsBox(2.0f, 0.5f);

      b2FixtureDef fd;
      fd.shape = &shape;
      fd.friction = 0.6f;
      fd.density = 2.0f;
      body->CreateFixture(&fd);

      b2MotorJointDef mjd;
      mjd.Initialize(ground, body);
      mjd.maxForce = 1000.0f;
      mjd.maxTorque = 1000.0f;
      m_joint = (b2MotorJoint*)m_world->CreateJoint(&mjd);
    }

    m_go = false;
    m_time = 0.0f;
  }

  void Keyboard(int key) override
  {
    switch (key)
    {
    case GLFW_KEY_S:
      m_go = !m_go;
      break;
    }
  }

  void Step(Settings& settings) override
  {
    if (m_go && settings.m_hertz > 0.0f)
    {
      m_time += 1.0f / settings.m_hertz;
    }

    b2Vec2 linearOffset;
    linearOffset.x = 6.0f * sinf(2.0f * m_time);
    linearOffset.y = 8.0f + 4.0f * sinf(1.0f * m_time);
    
    float angularOffset = 4.0f * m_time;

    m_joint->SetLinearOffset(linearOffset);
    m_joint->SetAngularOffset(angularOffset);

    g_debugDraw.DrawPoint(linearOffset, 4.0f, b2Color(0.9f, 0.9f, 0.9f));

    Test::Step(settings);
    g_debugDraw.DrawString(5, m_textLine, "Keys: (s) pause");
    m_textLine += 15;
  }

  static Test* Create()
  {
    return new MotorJoint;
  }

  b2MotorJoint* m_joint;
  float m_time;
  bool m_go;
};

static int testIndex = RegisterTest("Joints", "Motor Joint", MotorJoint::Create);
